In fact, this kind of understanding has a certain degree of one-sidedness.
The basic theoretical research and specific experiments show that the primary factor of the safety accident of power distribution equipment is the positive and negative change overvoltage when the power distribution system is damaged by lightning, especially the reverse change overvoltage damage safety accident. Now we analyze the whole process of the progress of the positive and negative transformation overvoltage, the lightning protection maintenance of the voltage regulator.
The positive and negative conversion of overvoltage.
When the low-voltage side of the part suffered by lightning, lightning flow invasion of low-voltage winding resistance, low-voltage winding resistance according to the neutral point grounding equipment into the road, grounding device electric flow Ijd in the grounding line resistance RJD caused pressure drop. This type of pressure drop makes the neutral line potential difference on the bottom voltage side rise substantially.
It accumulates with the overvoltage of the low-voltage winding resistance and seriously endangers the low-voltage winding resistance. At the same time, this operating voltage rises to the high voltage side according to the magnetic effect of the current of Kor-voltage and low-voltage winding resistance and accumulates with the phase difference operating voltage of Kor-voltage winding resistance, causing risky over-voltage of Kor-voltage winding resistance. Dry-type transformers.
This is called positive conversion overvoltage, which is caused by the lightning strike overvoltage of the low voltage winding, which is converted to the high voltage side according to the magnetic effect of the current, resulting in overvoltage of the high voltage winding.
When the high voltage side of the route suffered by lightning strike, lightning strike electric flow according to the high voltage lightning arrester charging and discharging to the road, grounding device electric flow IJD in the grounding line resistance RJD caused pressure drop. This kind of pressure drop in the bottom voltage side of the neutral line plays an effect, the low voltage side of the entrance and exit line is equivalent to according to the resistor grounding device. As a result, the vast majority of the operating voltage is added to the low-voltage winding resistance. Dry-type transformers.
In addition, according to the magnetic effect of the current, this pressure drop rises to the high voltage side in a variable ratio and accumulates on the DC voltage of the high voltage winding, causing over-voltage in the high voltage winding and leading to a penetration safety incident.
This situation is called a reversal overvoltage, where the low voltage side is transformed into the high voltage side by the magnetic effect of the current, because the high voltage side is struck by lightning.
Post time: Jul-18-2022
